Time delay switch with contacts providing flow restriction



April 26, 1966 DAVIS 3,248,492

TIME DELAY SWITCH WITH CONTACTS PROVIDING FLOW RESTRICTION Filed March 31, 1964 2 9 2 7 7 INVENTOR United States Patent O 3 248 492 TIME DELAY swircir WITH CONTACTS PROVIDING FLOW RESTRICTION Louis Davis, 5211 Bell St., Corpus Christi, Tex. Filed Mar. 31, 1964, Ser. No. 356,100 2 Claims. Cl. 200-33) This invention relates to a novel electric switch adapted to be interposed in the electric circuit of a light source for effecting a predetermined delay in the breaking of the electric circuit when the switch is moved to an ofi position, but which will not delay the closing of the circuit when the switch is moved to an on position.

More particularly, it is an object of the present invention to provide such an electric switch including an electrically conductive fluent material, preferably in the form of a liquid, such as mercury, to form a conductive bridge between two contact elements, in one position of the switch, and which material is displaced by gravity out of engagement with at least one of said contact elements, in an alternative position of the switch.

A further object of the invention is to provide an electric switch including a capsule having a cavity containing the mercury or conductive material, and which supports the two contact elements with portions thereof extending transversely across or through said cavity.

A further object of the invention is to provide an electric switch including a novel capsule supporting structure in which the capsule is demountably supported, to enable replacement of the capsule, if necessary, without completely replacing the electric switch.

Various other objects andadvantages of the invention will hereinafter become more fully apparent from the following description of the drawing, illustrating a presently preferred embodiment thereof, and wherein:

FIGURE 1 is a substantially central vertical sectional view through the switch;

FIGURE 2 is an enlarged fragmentary sectional view, taken substantially along a plane as indicated by the line 22 of FIGURE 1;

FIGURE 3 is a fragmentary sectional view of a part of the structure as shown in FIGURE 1 and showing-the parts in their other, alternate positions;

FIGURE 4 is a fragmentary side elevational view showing portions of certain of the parts of the switch looking from one side thereof;

FIGURE 5 is a view similar to FIGURE 4 looking in the opposite direction, and

FIGURE 6 is a diagrammatic view illustrating an electric circuit of which the switch forms a part.

Referring more specifically to the drawing, the delay action electric switch is designated generally 8 and includes a switch box 9, a switch support plate 10, a switch capsule 11, and a capsule support 12.

The switch box 9 has a front portion defined by spaced blocks 13 and 14, and defining an opening 15 in the front of said box, located between the blocks 13 and 14. The support plate 10 extends across the front of the box 9 and is fastened thereto by screw fastenings 16 which are anchored in the blocks 13 and 14. The plate 10 has an elongated opening 17 which registers with the opening 15. The block 13 is preferably formed integral with the box 9 while the block 14 is secured to the box by screw fastening means 18.

The capsule support 12 comprises an elongated body member, one end portion 19 of which constitutes a handle, while the other end portion 20 thereof forms a holder for the capsule 11. The inner part of the handle 19, adjacent the holder 20, is provided with a transverse bore 21 which is journalled on a pivot 22. The pivot 22 constitutes a screw having a threaded end 23 which threadedly engages in a threaded recess 24 of one side wall 25 of the box 9, and which opens inwardly of said box. Screw 22 extends transversely across the box 9 and has an opposite kerfed end 26 disposed in an opening 27 in the other side wall 28 of the box. Compression springs 29 are mounted on the pivot 22 and have remote ends hearing against the walls 25 and 28 and adjacent ends yieldably and frictionally engaging opposite sides of the handle 19, to resist rocking movement of the support 12 on the pivot 22 and to maintain such support in any position to which it is forcibly moved. As seen in FIGURES l and 2, the handle 19 extends outwardly through the opening 17 and is adapted to be manually engaged for swinging the support 12 between its full and dotted line positions of FIGURE 1.

The holder portion 20 is recessed to define alongitudinally extending socket 30 which opens outwardly of a distal end of said holder and in which the capsule 11 is slidably received. A cylindrical wall 31 of the holder 20 is formed of electrical insulating material and surrounds the cavity 30. Said wall 31 is provided on opposite sides thereof with slots 32 and 33, as seen in FIGURES 4 and 5, respectively. Each of said slots opens outwardly of the wall 31 at the distal end of the holder 20, and has a turned back inner closed end, so that the slots are each substantially J-shaped. The capsule 11 is preferably formed of glass or plastic and is provided with an elongated axially disposed chamber 34 which is partially filled with an electrically conductive material 35, such as mercury. The capsule 11 is of a size to fit slidably and rotatably in the cavity 30. Two electrical conductor elements 36 and 37 are supported by the body of the capsule and each extends transversely across said body and transversely through the chamber 34 thereof. Adjacent ends of the conductor elements or rods 36 and 37 are embedded in the capsule body and are sealed thereto so that the chamber 34 is sealed, and said conductor elements 36 and 37 have restricted portions 38 and 39, respectively, which extend transversely through the chamber 34 and which provide restrictor means for impeding the movement or flow of the mercury 35 longitudinallyof the chamber 34.

Remote exposed ends of the rods or conductor elements 36 and 37 extend outwardly from diametrically opposite portions of the capsule body and are adapted to engage in the slots 32 and 33, respectively, and combine therewith to form a bayonet joint. The straight longer portions of said slots are disposed diametrically opposite to one another in the wall 31 to receive the rods as the capsule 11 is inserted into the cavity 30. Cavity 30 has a recess 40 forming an extension of its inner end and containing a compression spring 41 which projects into said cavity and is engaged and compressed by the inner end of the capsule body, as the capsule is fully inserted and the rods 36 and 37 transverse the curved inner ends of the slots 32 and 33, respectively, when the capsule is twisted in the holder for moving the rods into engagement with the closed terminals of the curved ends of the slots, in which positions the rods are yieldably held by the spring 41 yieldably urging the capsule 11 outwardly of the socket 30, for holding said conductor rods in the closed slot ends. As seen in FIGURE 2, the distal ends of the rods 36 and 37 extend outwardly from the wall 31.

The block 14 is formed of electrical insulating material and has headed screws 42 and 43 engaging in and projecting from opposite sides thereof, and which form electrical connectors or contact posts to which are connected ends of wiring 44 of an electric circuit which includes a current source 45 and a light source 46. Conductor wires 47 and 48 are connected to and lead from the posts 42 and 43, respectively, and each is provided with a covering 49 of electrical insulating material. Each covering 49 has one end of an angular socket 50 of electrical insulating material connected thereto. The conductors 47 and 48 have exposed ends terminating in the sockets 50 to make electrical contact with the rods 36' and 37 when the other ends of said sockets are applied to the outer ends of said rods. Thus, as seen in FIGURE 2, the socket 50 containing the exposed end of the conductor element 47 receives the outer end of the conductor rod 36 which contacts said exposed end, and the other socket 50 receives the outer end of the conductor rod 37 for positioning the exposed end of the conductor element 48, which is contained therein, in electrical contact with said element 37.

Thus, when the support 12 is in its on position of FIGURE 1, with the handle 19 inclined upwardly from the pivot 22 and the holder 20 inclined downwardly therefrom, both restricted portions 38 and 39 are in electrical contact with the mercury 35, for bridging the gap between the spaced contacts 36 and 37 for thus completing the electric circuit including the current source 45 and light source 46.

When the handle 19 is manually engaged and swung downwardly for rocking the support 12 from its full line to its dotted line position of FIGURE 1, the holder 20 will be swung upwardly for supporting the switch capsule 11 in its off position, as seen in FIGURE 3. However, as the capsule 11 is initially moved to its ofl position of FIGURE 3, the restricted portions 38 and 39 will retard the flow of the mercury 35 from the outer to the inner end of the chamber 34, so that the mercury will remain in contact with both restrictors 38 and 39 for a predetermined time interval after movement of the switch to its ofi. position, so that electric circuit 44 will not be interrupted until the downward movement or flow of the mercury has been substantially completed, and at which time the level of the surface of the mercury 35 will be between the restrictors 38 and 39, with the restrictor 39 submerged in the mercury and with the restrictor 38 disposed above and completely out of contact with the mercury, so that electric circuit is broken.

However, when the support 12 is rocked clockwise from its dotted line or off position in FIGURE 1 to its full line or on position of said view, the part of the mercury 35 which is disposed between the restrictors 38 and 39 will flow unimpeded toward and into engagement with therestrictor 38 for promptly completing the electric circuit without any delay.

It will be readily apparent that should the switch capsule 11 become damaged, it may readily be replaced, without replacing or discarding the remainder of the switch 8, by removing the supporting plate and the pivot screw 22, so that the capsule 11 with its contacts 36 and 37 can be removed and replaced, afterwhich the support 12 can be reassembled in the box 9 and the plate 10 replaced.

Various modifications and changes are contemplated and may be resorted to without departing from the function or scope of the invention as hereinafter defined by the appended claims.

I claim as my invention:

1. A delay action electric switch comprising an elongated capsule having an elongated chamber disposed longitudinally of the capsule, means supporting the capsule for rocking movement about a substantially horizontal axis disposed crosswise of the capsule, an electrically conductive fluent material partially filling the chamber, flow restriction means for restricting the flow of said fluent material, said flow restriction means comprising a pair of electrical contact elements extending across and anchored in the capsule in spaced apart relation to one another and including parts extending transversely through the chamber and spaced from the ends thereof, said supporting means being swingable about said horizontal axis between two positions in which the capsule is inclined in opposite directions, said fluent material being in contact with both of the contact elements in one of said positions to form a conductor bridge therebetween, and the fluent material being in contact with only one of the contact elements in the other of said positions for breaking the electrical connection therebetween.

2. A delay action electric switch as in claim 1, said parts of the contact elements being spacedlongitudinally of one another relative to the longitudinal axis of said chamber and being spaced from the chamber ends so as to retard the flow of said fluent material lengthwise of said chamber for maintaining the fluent material in engagement with both of said contact elements for a predetermined time interval after movement of the capsule to said last mentioned position and for permitting the fluent material to promptly resume and retain contact with both of said contact elements when the capsule is initially moved to said first mentioned position.

References Cited by the Examiner UNITED STATES PATENTS 1,611,594 12/1926 Knutsson 200--5l.13 X 2,800,537 7/1957 Hesh 200-33 BERNARD A. GILHEANY, Primary Examiner.

H. M. FLECK, Assistant Examiner. 

1. A DELAY ACTION ELECTRIC SWITCH COMPRISING AN ELONGATED CAPSULE HAVING AN ELONGATED CHAMBER DISPOSED LONGITUDINALLY OF THE CAPSULE, MEANS SUPPORTING THE CAPSULE FOR ROCKING MOVEMENT ABOUT A SUBSTANTIALLY HORIZONTAL AXIS DISPOSED CROSSWISE OF THE CAPSULE, AN ELECTRICALLY CONDUCTIVE FLUENT MATERIAL PARTIALLY FILLING THE CHAMBER, FLOW RESTRICTION MEANS FOR RESTRICTING THE FLOW OF SAID FLUENT MATERIAL, AND FLOW ELEMENTS EXTENDING ACROSS AND ANCHORED ELECTRICAL CONTACT ELEMENT EXTENDING TO ONE ANOTHER AND IN THE CAPSULE IN SPACED APART RELATION TO ONE ANOTHER AND INCLUDING PARTS EXTENDING TRANSVERSELY THROUGH THE CHAMBER AND SPACED FROM THE ENDS THEREOF, SAID SUPPORTING MEANS BEING SWINGABLE ABOUT SAID HORIZONTAL AXIS BETWEEN TWO POSITIONS IN WHICH THE CAPSULE IS INCLINED IN OPPOSITE DIRECTIONS, SAID FLUENT MATERIAL BEING IN CONTACT WITH BOTH OF THE CONTACT ELEMENTS IN ONE OF SAID POSITIONS TO FORM A CONDUCTOR BRIDGE THEREBETWEEN, AND THE FLUENT MATERIAL BEING CONTACT WITH ONLY ONE OF THE CONTACT ELEMENTS IN THE OTHER OF SAID POSITIONS FOR BREAKING THE ELECTRICAL CONNECTION THEREBETWEEN. 